A flex wing apparatus is any apparatus which derives its support or motive power, in whole or in part, from a flexible wing. Example of flex wing apparati include sailboats, board sailing apparatuses, hang gliders and land sailing apparati.
The performance of a flex wing apparatus is dependent upon the efficiency of its flex wing. In order to tailor a flex wing for particular wind conditions, it is often necessary or desirable to adjust the camber of the wing.
For example, a sailboat or board sailing apparatus typically comprises a sail which is stiffened by resilient battens carried by batten pockets in the sail. The sail can be variably tensioned by an outhaul, and this can be used to provide some degree of camber adjustment in the sail. Unfortunately, however, when it is desired to increase the camber of the sail, the compressive forces on the battens push them forward around the sides of the mast thereby providing discontinuities in the wing and materially distorting the airfoil shape of the sail. This in turn reduces the efficiency of the sail and degrades performance.
In an effort to overcome this problem, it has been proposed to utilize a large, expensive mast of airfoil configuration and to couple the leading edges of the battens to the trailing edge of the mast. The mast is pivotable generally about its longitudinal axis, and with this arrangement, camber can be induced in the sail. However, in order to reduce the weight of this mast to an acceptable limit, it must be constructed of exotic expensive materials which make the cost of this construction very high.